Seized Nitro Motor - RC Groups
Shop our Airplanes Products Drone Products Sales
Thread Tools
Sep 20, 2012, 10:36 AM
Registered User

Seized Nitro Motor

Ok so i went to a garage sale and this guy was selling all of his RC stuff (3 planes and a Heli and several radios and flight box) for dirt cheap, so i bought them. He said he hasnt flown them in 6 months and they all work. Well i finally got a chance after month from buying them to take one of them out. Before i was going to take it out i was going to fire one of them up. Well i found out that on one, the motor is seized up. I have read what to do if i had the motor OFF (noticed i said off) the plane.....but the guy i bought this from Epoxied the screws to the motor and the plane, and the bracket for the motor, he did the same to it... epoxied all the screws there... So my question is, how do unseized this motor since i cant get it off, or is there a way i can get the motor off w/o destroying the plane in the process?
Sign up now
to remove ads between posts
Sep 20, 2012, 11:05 AM
Registered User
captscotty's Avatar
i guess you could drill them out to remove the head of the screw. just start with a really small bit and gradually increase in size until the head of the screw comes off. pain in the butt but about the only option. why in the world would anyone cover screws with epoxy? maybe ought been a warning sign from the getgo...
Sep 20, 2012, 12:25 PM
-insert witty saying here-
Hemikiller's Avatar
Remove the glow plug and fill the engine with glow fuel, it does a fairly good job of dissolving castor oil residue.If that doesn't get it turning, warm the engine with a hair dryer or heat gun. Most stuck engines are the result of dried up castor oil and heat will help soften the residue.

Heat will also soften epoxy enough so that you might be able to chip it away from the screws. If all else fails, grind the heads off the screws with a Dremel.
Latest blog entry: ECSF 2017 SWap Meet - 4/2/17...
Sep 20, 2012, 12:26 PM
Registered User
I didnt know until just this last week, So i guess i need to take the motor off so i can get it unstuck then huh?
Sep 20, 2012, 12:55 PM
Registered User
I have had pretty good luck freeing up engines with good old ATF. You could try taking the glow plug out and getting some ATF in the top of the cyclinder. Pour a bunch down the carb as well to free up the crank. Don't be afraid to put lots in, you can always drain it back out, and give it a quick glow fuel flush.

Another thing I have done, which you may be able to do with the engine still installed, is pull the whole head of the cylinder and work the ATF in the top end that way. I have also taken the back plate off the case and dumped it in through there too.

Like Hemikiller said, using glow fuel would work too, I just like the cheap brands of ATF because it is cheap, comes in small jugs, and works well. It also works pretty good for anti-corrosion protection if you are not going to run the engine for a while.
Sep 20, 2012, 01:02 PM
Registered User
The carb is probably stuck too. Take the glow plug out, remove the carb and remove the muffler. Squirt WD40 or some kind of penetrating oil into all 3 openings. Heating it up with a heat gun or hair dryer may help as already mentioned. Let it sit overnight. Soak the carb in a solvent by itself.
Sep 20, 2012, 01:19 PM
Registered User
The probability of just using some high heat like a commercial heat gun or even a torch to heat the head and carb will loosen it up if the cause is from castor oil congealing (a high probability). I've had little luck with fluids like ATF, WD40 etc. unless you want to leave it soak for a month or two. You can also use heat to loosen the mounting screws, a gun type of a 100 watts or so soldering iron might work well there, just heat each screw as you try to torque it loose.
Sep 20, 2012, 02:34 PM
Registered User
Just put on a prop, pick up your covering heat gun and put it on high, heat the engine up hot then roll it over by hand, move the arm on the carb too so it is loosened up. Then pull the plug and put in some glow fuel and rotate the engine some more. I like to squirt in some marvel mystery or air tool oil, leave the plug out and roll the engine over with my starter.
There you are, a freed up engine. Trick time: use that heat gun on the screws that have the epoxy on them and unscrew them while still hot. Heat melts or softens epoxy.
When I have made a mistake in a build I just grab the heat gun, soften up the epoxy and remove the part, it doesn't even harm the wooden part so it can then be used in the correct location!!
A mistake in a build!!! Me?? Well I think I recall it happening once!!
Sep 20, 2012, 11:06 PM
Registered User
Well here is what i did, through the card and the hole were the glow goes, i squirted wd40 into it. Then let it sit a hour, then went back and squirted more in and started to turn it back and forth then squirt more wd40 in there....let it sit and then start process over again. While i was out i went to local hobby shop to see if they had anything to lube it up once i got it free... and they introduced me to this stuff called compression x... it help free up motors and lube it up at the same time. Right now i have sitting with a little bit of it sitting in the motor over turns over but dunno if it is 100% yet... I hope this is work soon. I want to fly monday LOL

*** Correction on the stuff i bought at the hobby shop.. It is called Corrosion X
Last edited by smokingmango; Sep 21, 2012 at 10:19 AM.
Sep 20, 2012, 11:11 PM
Registered User
Sounds much easier then adding heat and rolling it over, I will give it a try next time to see how well it works.
Oct 05, 2012, 10:12 AM
KV4PL, FAA 107 Certified
FloridaFlyBob's Avatar
I had 2 os46's that sat for 7 years, I couldn't turn the props on either engine. I put a little fuel in the glowplug hole and in the carb let it sit for a little while and the both freed up. I had to pull the piston on 1 engine as the ring was stuck soaked the piston for a while and that was ok as well.

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Help! T28 motor seizing after one flight... crashbro Scratchbuilt Indoor and Micro Models 3 Jul 24, 2012 11:25 AM
Help! Electric motor seizing. Dont know what to do? maverick64 Electric Plane Talk 8 Mar 26, 2012 01:14 AM
Discussion My motor seized and smoked..why? felixk Electric Plane Talk 36 Mar 05, 2012 03:06 PM
Discussion Nitro Hammer Engine Seized?? greenie_au Racing Boats - Internal Combustion 2 Jul 26, 2009 10:17 AM
Tiger Moth floating nose-down = seized motor!!! CheeseWing Parkflyers 13 Aug 14, 2002 08:07 PM